An Ultra Voltage Gain Step-Up DC/DC Converter with Low Complexity and Common Grounding Design

Abstract

DC microgrids are in high demand due to the integration of renewable energy supplies (RES), including fuel-cells and solar photovoltaics. In this application, a high voltage gain (VG) DC/DC converter is an indispensable module that supports the connection of low voltage (LV) RES to the high voltage (HV) DC grid. This article presents an ultra-VG step-up DC/DC converter (SDC) featuring low complexity and a common grounding design. The proposed SDC utilizes a total of 10 elements in the circuit and operates with dual duty ratios. With this design and operation, ultra-VG is attained with low duty ratios for individual switches, which do not exceed 0.5. Therefore, switching at extreme duty ratio is obviated. The analysis of SDC is presented, which includes steady state operation, VG derivation in ideal and non-ideal modes, parameter design, and practical power loss. With a 200 W load power, the proposed SDC prototype is experimentally evaluated, and test results are displayed where the practical VG attained is 9.525 with dual duty ratio of switches valued at 0.4, gaining 95.2% efficiency. The extensive comparisons reveal the proposed SDC’s significant contributions over existing SDCs, including improved VG for low duty ratios for individual switches along with a common grounded low complexity design. Hence, the proposed SDC is attractive for ultra-VG application.